Disclosed in JP2006-17158A is an example of a cable-type driving force transmission mechanism, which is adapted to an electric parking brake apparatus for a vehicle. An electric actuator of the cable-type driving force transmission mechanism disclosed in JP2006-17158A includes a housing attached to a vehicle body (a support member), an electric motor attached to the housing, a conversion mechanism that is provided within the housing and converts a rotational driving force of the electric motor into a linear driving force, and a driving member (an equalizer) that is linearly driven by the linear driving force, which is generated by converting the rotational driving force of the electric motor by the conversion mechanism. Further, a cable of the cable-type driving force transmission mechanism disclosed in JP2006-17158A includes an inner wire, which is detachably connected to the equalizer at an end portion of the inner wire and which is connected to an actuation member of each parking brake apparatus at the other end of the inner wire, and an outer tube, which covers an outer circumference of the inner wire except for both end portions thereof. The outer tube is detachably and immovably connected to an outer tube attachment portion, which is provided at the housing, at an end portion of the outer tube at a housing side. Further, the outer tube is immovably assembled to a retaining member for retaining the actuation member at an end portion of the outer tube at an actuation member side.
In the electric parking brake apparatus for the vehicle disclosed in JP2006-17158A, a pair of through holes, which are provided at respective output portions of the equalizer (i.e. swing portions formed in a U-shape to open towards respective inner wires) and which pass through the respective output portions of the equalizer in a direction orthogonal to a wire longitudinal direction, and a notch, which is provided at one of the through holes for opening a portion of the through hole in a direction orthogonal to the wire longitudinal direction and the through hole, are adapted as a connection means for connecting each of the output portions of the equalizer and each of one end portions of the respective inner wires. Further, an I-shaped connecting pin portion is integrally provided at one end portion of each inner wire so as to be orthogonal to the wire longitudinal direction. A portion of I-shaped connecting pin portion is inserted into the pair of through holes via the notch, so that the I-shaped connecting pin portion is fittedly fixed on the pair of through holes at both end portions of the I-shaped connecting pin portion.
In the electric parking brake apparatus for the vehicle disclosed in JP2006-17158A, an annular groove is formed on the outer tube, which covers the outer circumference of the inner wire, at the end portion of the outer tube at the housing side. A portion of the housing is fit into the annular groove, so that the end portion of the outer tube at the housing side is immovably retained at the housing.
In the electric parking brake apparatus for the vehicle disclosed in JP2006-17158A, the I-shaped connecting pin portion, which is provided at one end portion of each inner wire, needs to be attached to each of the output portions (swing portions) of the equalizer, which is provided within the housing, and the end portion of each outer tube at the housing side needs to be attached to a portion of the housing in the manner where the portion of the housing is fit on the annular groove formed at the end portion of each outer tube at the housing side. Therefore, each cable needs to be attached to the housing during an assembly process of the electric actuator. In a state where the equalizer, the inner wires, outer tubes and the like are assembled to the housing, the housing and the cable need to be handled as a unit. In other words, relatively long and unhandy cables need to be handled in a process of a production line of the electric parking brake apparatus, which may deteriorate productivity.
A need thus exists to provide a cable-type driving force transmission mechanism which is not susceptible to the drawback mentioned above.